Improvements from Alfred:

- Add new SDL_WINDOW_FULLSCREEN_DESKTOP video mode, makes a fullscreen window the size of the desktop (i.e no window manager mode change)
- Fix crash in warp mouse if you specified null as the window
- Added new SDL_VIDEO_MINIMIZE_ON_FOCUS_LOSS Hint, if set to 0 then don't minimize a fullscreen window on focus lost (if not set or set to non-zero then minimize on focus loss)

src/events/SDL_mouse.c

@@ -379,6 +379,12 @@ void
 SDL_WarpMouseInWindow(SDL_Window * window, int x, int y)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
+	
+	if ( window == NULL )
+		window = mouse->focus;
+	
+	if ( window == NULL )
+		return;
 
     if (mouse->WarpMouse) {
         mouse->WarpMouse(window, x, y);